1995 Ford Taurus OBD Code 558

Car was running rough and cooling fan would not turn off when ignition was in the on or run position. Reviewed schematics and coolant temperature sensor was out of spec with respect to resistance test. Replaced sensor - didn't fix fan problem. Ran voltage tests at Control Relay Module and found EHC relay in closed position at all times. Replaced CRM and fan problem was solved. Checked EGR valve regulator solenoid and found it was bad - replaced it and engine now idles correctly and runs great but I still get a 558 code. Took the vehicle on a road test, accelerates smooth, lots of power, but at about 65MPH check engine light came on (it had not come on until the road test) andwhen I ran another OBD test I still get the 558 code but now a 332 Insufficient EGR flow detected code as well. EGR valve operates correctly under light vacum, verified intake port is clear, all vacum lines are intact. Any sugestions?

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Wednesday, October 1st, 2008 AT 11:24 PM

12 Replies

JACK42

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The insufficient EGR code is most likely the PFE (pressure feedback sensor) They go out often, the sensor sees backpressure changes in the exhaust system that occur when the EGR opens and closes. The PFE can also cause your code 558

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Thursday, October 2nd, 2008 AT 7:58 AM

LSHOOK

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Replaced the PFE. Took for a road test - 70MPH for about 15 minutes on the highway - took an exit to turn back for home and when speed dropped to 65MPH check engine light came back on. Parked the vehicle and turned of the ignition. Waited a minute and started up - no check engine light. Ran OBD test and still reads 558 and 332. Still runs great - no hesitation or rough idle and smooth throughout acceleration range with good firm shift points.

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Friday, October 3rd, 2008 AT 8:58 PM

JACK42

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Is this a 3.0 or a 3.8 liter? Best bet is to get the8th digit of the vin#. You say intake passages are clear? So if you manually pull tehEGR valve on at idle the engine will almost die?

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Saturday, October 4th, 2008 AT 7:47 AM

LSHOOK

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It's a 3.0 - 8th digit of VIN is U. I had put a vacum test on the EGR during my initial tests and it works properly - engine idles drops under vacum then comes comes back up when vacum is removed.

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Monday, October 6th, 2008 AT 8:07 AM

JACK42

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How much does it drop? Should stumble hard, if pulled on fast enopugh should almost kill the engine

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Monday, October 6th, 2008 AT 11:09 AM

LSHOOK

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It stalls the engine almost to the point of kiiling it.

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Monday, October 6th, 2008 AT 7:51 PM

JACK42

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The 558 is most likely creating the 332. Need to run a vacuum line from the EGR line to a gauge where you can see it while driving. The insufficient flow could be created by the fact the EGR solenoid isnt letting vacuum to the valve while driving. Take it for a drive around 60 mph part throttle cruise to see if the vacuum gauge reads anything, should be giving some to the EGR valve to open it, if not could be the EGR solenoid is bad

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Monday, October 6th, 2008 AT 9:32 PM

LSHOOK

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Hooked up the vacum gauge (put a tee in at the EGR valve) and went for a test drive - no vacum whatsoever, test engine light comes on now @ 45MPH and stays on until ignition is turned off - does not come on when vehicle is initially started. At idle about 15Hg manifold vacum at the EVR solenoid relay. Verified again that all vacum lines are intact. Solenoid tests @ 50 ohms between the terminals, grounded pin 33 while idling and idle dropped significantly both of which I understand are correct. Disconnected EVR solenoid relay power and no vacum at EGR while idling. I had replaced the EVR solenoid as the initial step in the process (picked up new one at a local Ford dealer) so is it possible I got a defective unit or is it possible the computer is bad?

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Tuesday, October 7th, 2008 AT 10:39 PM

JACK42

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The only way to tell without a scanner hooked up is to tap into the signal wire for the solenoid and see ifit is getting voltage from the ecm when at cruise speed

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Wednesday, October 8th, 2008 AT 7:22 AM

LSHOOK

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Took it for a test drive and it shows battery voltage throughout the drive. Check engine light came on @ 72MPH and stayed on with no change in voltage status at the EVR solenoid relay. After turning off the ignition and restarting check engine light does not come back on immediately.